<p>what was the question?</p>
<p>f(x) = f^1(x)?</p>
<p>f(x) = f^-1(x)</p>
<p>...dont cross the given function? Anyone remember that one? I put 0.</p>
<p>There is no reason except the definition of the inverse requires a switch of x and y, which is useful and special since it undoes another function.</p>
<p>You can craft up ways to make functions reflect over y = -x, but they would not have any significance.</p>
<p>yes, so if u do another example only symmetrical about y=x, it will work. but if it is only symmetrical about y=-x it will not work. just think about it, when you take the inverse of somthing you reflect about teh line y=x and if it is already symmetrical about that line, no change will occur and it will be identical.</p>
<p>"If one represents the function f graphically in an x-y coordinate system, then the graph of f −1 is the reflection of the graph of f across the line y = x" (<a href="http://en.wikipedia.org/wiki/Inverse_function)%5B/url%5D">http://en.wikipedia.org/wiki/Inverse_function)</a>.</p>
<p>Well I guess that settles it...who knows.</p>
<p>How many lines could be drawn from the points ABCDE. It was a straight line with those points on it. I put C, which was 10. Q number 8 I believe.</p>
<p>Yes, the answer is 10. There are five points of which you choose any two to form a line segment. The answer is 5C2 = 10</p>
<p>I couldn't believe I couldn't get that one until the very end lol</p>
<p>Did I already ask about the standard deviation problem? i put 8,10,10,10,12.</p>
<p>Oh yeah, there was another about averages. I think it was mode<median<mean. I remember mean being biggest, with mode being smallest.</p>
<p>What was the period for the tangent question (I put pi/2)</p>
<p>and what about that one where we check functions (I put I and III)</p>
<p>I think the functions one was I and III, from what everyone else was saying, but I didn't get it.</p>
<p>Nope, you didn't ask about the standard deviation question, but I put the same answer. The mode, median, mode question was as you said. As for the period of |tan2x|, I believe it is pi/2. What do you mean by the problem where we check functions--do you mean finding x when f(x)=g(x)? That would indeed be I. and III. then.</p>
<p>Could you explain how you got that answer for the deviation? I just guessed, since those look to have the least deviation out of all of the answers.</p>
<p>Anyone else remember any random problems? :)</p>
<p>Yes, that is the fastest way to solve the problem. The way I did to check was tediously plug each list into my TI-89 then calculated the standard deviation that way. I went to Apps->Data Matrix Editor and chose a List that I stored under variable a. I plugged everything into c1, then went Home, to 2nd+5 math menu, Statistics, stdDev(a).</p>
<p>There are ways to calculate it on paper, but I don't know them since I have not taken statistics.</p>
<p>sqrt(SUM(mean-x)^2)</p>
<p>chance of two random numbers adding up to 100. .5</p>
<p>also for verification.. y= x/(x-1) is its own inverse. If you graph it you will find that it is symmetric about y=x but not with y=-x</p>
<p>was there a problem in which the sin of x was -.877 (i think choice a)
anyone remember that one?</p>
<p>I couldn't get that one about the random numbers adding to 100! argh</p>
<p>There was a problem about cos, sin whatever. I got 1-x^2</p>
<p>I think it was something with f(g(x)), and something with sin cosine. Don't remember excactly, but I got 1-x^2.</p>
<p>Was that the problem which involved finding the angle using the Law of Cosines? If so, the sine turned out to be 0.866 (sqrt[3]/2) because sine is positive in the second quadrant.</p>
<p>I got 1-x^2 for the question you are talking about also. I believe it was f(g(x)) = cos^2(x) and g(x) = sin(x). What is f(x)?</p>
<p>Because f(g(x)) = f(sin(x)) = cos^2(x) = 1-sin^2(x). Replacing sin(x) with x we get f(x) = 1-x^2</p>
<p>f(x)= sinx g(f(x))= cos^2x you were to find g(x) i believe. The answer was 1-x^2</p>